Benzal-alpha-methyl-alpha-phenylhydrazones and derivatives as ultraviolet absorbers



BENZAL t METHYL a PHENYLHYDRAZONES JSASEBEIRQERIVATIVES AS ULTRAVIOLETAB- James A. Van Allan, Rochester, N. Y., assignor to Eastman KodakCompany, Rochester, N. Y., a corporation of New Jersey No Drawing.Application February 19, 1954,

Serial No. 411,587

20 Claims. (Cl. 117-333) This invention relates to materials which areultraviolet absorbers and to their use in the fabrication of lightfilters, light protective wrappings, organic plastic materials and thelike. More particularly, this invention relates tobenzal-a-methyl-u-phenylhydrazones.

It is well known that many organic substances are affected by the actionof ultraviolet light. For instance, various colored objects, textilesand dyed substances will fade when exposed to long periods of sunlight.This appears to be particularly true of colored articles havingrelatively thin cross sections such as colored photographic prints,transparencies, dyed organic fibers and the like.

It is known that organic plastics, resins, film-forming materials andthe like become colored, brittle and eventually deteriorate when exposedto sunlight. In order to vitiate the deleterious and damaging effect ofsunlight upon'plastics and other materials, incorporation of stabilizerssuch as, for example, 4-benzoyl resorcinol (U. S. Patent No. 2,568,894)and the like, have been suggested by the prior art. However, while manyof these compounds are excellent ultraviolet absorbers, their absorptioncharacteristics may change considerably when the pH is on the alkalineside. In some instances, films containing certain ultraviolet inhibitorshave a definite yellow color when the pH is greater than 8. Furthermore,some of these compounds lose a great portion of their light stabilitywith an alkaline pH. In addition, some of these inhibitors are known tobe very active couplers which makes them unsuitable for manyphotographic purposes.

I have found that benzal-a-methyl-a-phenylhydrazones are effective asultraviolet absorbers when incorporated in surface coatings andphotographic material or when used in such plastic materials aspolyvinyl chloride, cellulose acetate butyrate and the like.

Accordingly, an object of this invention is to provide a light filtercapable of substantial absorption in the region of the near ultraviolet.Another object is to provide a light filter having a substantiallycomplete and preferential absorption of light within the wavelength bandof 30004000 A. Another object of this invention is to provide newcompositions of matter which are polymeric compounds havingbenzal-a-methyLu-phenylhydrazone or a derivative incorporated therein toprotect these polymers from breakdown and color fading due toultraviolet light. A further object of this invention is to provide anultraviolet inhibitor which is independent of pH for stability, remainssubstantially waterwhite after ultraviolet absorption and is compatiblewith photographic applications.

I have found that benzal-a-methyl-a-phenylhydrazone fulfills therequirements for a satisfactory and successful ultraviolet inhibitor foruse in a great variety of applications. The hydrazones which I havefound to be preferred for ultraviolet inhibitors include the following:

4'-isopropylbenzal-a-methyl-a-phenylhydrazone4'-butoxybenzal-tit-methyl-a-phenylhydrazone 2,763,566 Patented Sept.18, 1956 4'-hydroxybenzal-a-methyl-a-phenylhydrazone 2',6' di tert.butyl 4 hydroxybenzal a methyla-phenylhydrazone2',4'-dichlorobenzal-a-methyl-a-phenylhydrazone3,4'-dichlorobenzal-a-methyl-ot-phenylhydrazone4-fi-Hydroxyethoxybenzal-s-methyl-a-phenylhydrazoneo-Methoxybenzal-a-methyl-a-phenylhydrazone4'-chlorobenzal-u-methyl-a-phenylhydrazoneZ-chlorobenzal-tat-methyl-a-phenylhydrazone2,6-dichlorobenzal-oc-methyl-a-phenylhydrazone In general, compoundshaving the hydrazone configuration cannot be depended upon to be stable,and compounds similar to those that I have found useful in thisinvention are notably unstable, particularly upon eX-' posure toultraviolet light. For instance, benzophenone phenylhydrazone isunstable and breaks down upon standing overnight in a dark place,resulting in the formation of a strong yellow color.Benzalphenylhydrazone which may be regarded as the parent compound, isextremely light-sensitive and is quickly decomposed by the action oflight into a mixture of dark colored degradation products, among themB-benzoylphenylhydrazone, benzaldehyde, benzoic acid, etc. In sharpcontrast, a representative a-methyl derivative,o-methoxybenzal-a-methyl-aphenylhydrazone showed no ultravioiet fadingwhen exposed in gelatin to normal radiation over a period of severalweeks. i

The ultraviolet absorbing capacity, the stability, and the absence ofunwanted side reactions, have been particularly marked in the tests withpolyvinyl chloride and butadiene copolymers. When used with celluloseacetate butyrate under outdoor weathering conditions in Arizona, theyhave shown good absorbing properties.

The following table illustrates but is not intended to limit thepractice of this invention. with respect to the use of thesecompositions in polymeric materials:

These compositions were also tested for stability in gelatin. One gramof the a-methyl-a-phenylhydrazone was dissolved in 2 cc.dibutylphthalate and this solution mixed in 20 cc. 10% gelatin solutionat 40 C. The mixture was passed through a colloid mill, and theresulting fine dispersion was coated on gelatin subbed glass plates at40 C., chilled to set, and dried. Substantially complete andpreferential absorption of light within the wavelength band of 3000-4000A. was observed.

In the above table the polymer is composed as follows:

50 parts polyvinyl chloride 50 parts polymeric plasticizer (such asParaplex 6-60) 2 parts antioxidant (such as Ferro 200) 2 parts advancedresin stabilizer #3 2 parts acrowax C (ethylene distearamide) (parts areby weight) Paraplex G-60 is a polymerized ester of a high molecularweight, unsaturated hydroxy acid and a low molecular weight alcohoL IFerr'o 200 is cadmium Z-ethyIheXoate; I I

I One'ahntrrlred parts by weight'of this polymeric tcom'po-' I I sitionwere used wjthq4 parts of a derivative 01% benzalm; I i

=a-methyl-u-phenylhydrazone. I

' 'Tfie:b'endingi-modulus was determined 'acc ordingvto the about. 4% ofa benzal derivative-of; m-methyl-wphenyls I 1; An ultraviolet radiationabsorbing composition of I matter comprising a sheet of lighttransmitting plastic I material I, having iinco'rpor'atedithereinianultraviolet ab-v sorbing' amounit of benzal-wmethyI-wphenylhydrazone;I I 2. Anorganiopolymeric composition containing a ma I I II 'terialIiselectedxfrom the class consisting ofpolyvinyl'chlo" zone derivative iis I hydr'azone; v I

I I 9; A product according to -claim-Zwliereio the h ydrae zone:derivative is: 4'-isopropylbenzal-wmethylwephenyh hydrazone v I I 10;.Aproduct;

according to'cloini 2' wherein-tile :zoner, derivative; i is 4I'-butoxybenzal-u-met1;1yl-a+pheny1.

ihydrazomb I I I I I 11. Aproduct according to claim 2 vvlnereintlre-ihydrai 47-hydroxyl;enzalra-methylfl -phenyh i I 12.. A prodtict;according to claim 2 wl1erein tl1eghydrai g :zone derivative: is2,4-dichlorobenzal-ui-methybu-phenyl? I I I I .hydrazonei; It I I 13.Aproduct accordingto-claim-Z wherein'the hydra:

' ride butadieneaand Cellulo'selziCe'tzite butyrate-having-ins zonederiv ive isI 3,A-di hIOm mZ -wm hYLu phenyh. c ox'rporated' thereinabout 4% of a "derivative:of-benzal w I methyl arphenylhydrazonet' I 3photographic print having: a light transmitting :1 I coatingthereoncontaining ta. derivative of benzabw: methyl a-plienylhydrazone.{I I I 43 -A process for protecting a photographic ris'srwmf Iultraviolet deterioration comprising depositingabenzal derivajtive of jwinethyl-a-phenylhydrazone in a: suitable I I carrierupo'n asnrfaceoftheprins I I I1 I '5; A process for protecting .an organic polymericcomiposition c'zoirtair iing is material selected from the classconsisting-of polyvinyl chloride; :buiadiene; and cellulose Iacetatebutyrate frorn' ultraviolet deterioration compris- :i'nglia'ddingf about 4% of a ben'zal'derivative ofm-l'flfl'lylaphenylhydrazone to the organic polymeric composition; I I

6;. A-process for protecting organic polymeric composi- I II I I I I I II v I I I I I I I I tion' containing a; material selected from the classconsist-i I I 1 I .19. Ap s c d n c a m w hy r I L in}; ofpolyvinylchloride; butadiene, and cellulosel'acetate I ;3, -dichlorobonzfll-o-m iy f iphenyl I I I butyrate from ultraviolet deterioration I comprisingcoat 2 i'ngztheamaterialwith a lacquer containing a benzal: de'riva-i I1 tive of a mefhyl ii-phenylhydrazone in .aLcarrieZr onto the I ipolymeric material.

, 7 i 7, A process for protecting :a. polyvinylchlorideIcomprisinglmoleoularly dispersing indie-polyvinyl chloride azonederivative :is; 2,4-dichiorobenzabu-methyl-a-phenyl- I hydrazone. II

hydrazone; 1 I I I I I I I I I I 14. A product; according to claim 2whereinthe hydra I I I t jzone derivative" is 4-cl lorobenzal:e;;methyl-a phenylhydra I I I I I II .hydrazone; I, I,

, I I 15." Aprocess according to: clainll wherein hydra-Q I Q y l j l II zone derivative: :4i-isopi'opylbenzal z-methyhaeplienyb I I I I i I Ihy a n p I I 16.. A processaocording to, claim, 5; whereintheg hydra- II I I I I zone: derivative is; 4-buto3ybenzal ve-methyl e-phenyl- I :hydrazone.- I ;l7il';Aiprocess 'zonjederivative is;- '4hydroXybenzaI-a-mcthyhu:phenyb I 18.; Aaprocess:accordingto; claim 5wherein tlie hydraeg I I z i zone. 7 I v "UNITED STATESiPATENTS"2,129,132 Hunter Sept. 6, 1938 2,241,239

, gkef ere'n cesfiited in the file of this patent I I 5 Carroll et al.May 6, 194i

4. A PROCESS FOR PROTECTING A PHOTOGRAPHIC PRINT FROM ULTRAVIOLETDETERIORATION COMPRISING DEPOSITING A BENAL DERIVATIVE OFA-METHYL-A-PHENYLHYDRAZONE IN A SUITABLE CARRIER UPON A SURFACE OF THEPRINT.